Determination of the translational temperature of the high altitude terrestrial thermosphere from the rotational distribution of the 5.3 µm emission from NO(v=1)

The rotational distribution of vibrationally excited nitric oxide produced by impacts with atomic oxygen is investigated using a quasiclassical trajectory approach. The present study confirms the earlier result that the nascent rotational distribution may be described by a Maxwell‐Boltzmann (MB) distribution. It further shows that the temperature describing the nascent distribution is about 25% lower than the translational temperature and equals it after 3 to 5 collisions. Translational temperature as function of altitude is derived from the nighttime rotational distribution of the 5.3 µm emission observed by c ryogenic i nfra r ed r ad i ance for s huttle (CIRRIS 1A) and compared with the mass spectrometer incoherent scatter (MSIS) model temperature. Because of the strong 5.3 µm emission this method has larger signal than the N + O radiative recombination currently used to determine the nighttime thermospheric temperatures.